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Transcript of VMware iSCSI final2 - Dell · PDF file VMware and iSCSI This section will describe the steps...

  • May 2007

    Dell iSCSI Storage for VMware

    By Dave Jaffe Dell Enterprise Technology Center

    Dell | Enterprise Technology Center dell.com/TechCenter

  • May 2007 Page 2 Dell Enterprise Technology Center

    Contents Executive Summary ....................................................................................................... 4  Introduction .................................................................................................................... 5  The Dell iSCSI Storage Arrays ...................................................................................... 7 

    The PowerVault NX1950 .......................................................................................... 7  The Dell/EMC FC/iSCSI Arrays ................................................................................ 7  The Dell/EMC AX150i ............................................................................................... 8 

    VMware and iSCSI ........................................................................................................ 10  ESX Configuration ................................................................................................. 10  Connecting the ESX Server Host to the iSCSI Array .......................................... 11  Configure iSCSI Software Initiator in ESX ...................................... 11 

    Configure Target Storage Array and Create the LUNs ................... 12 

    Format Storage................................................................................ 12 

    The Test Setup ............................................................................................................. 13  iSCSI Performance Comparison ........................................................................... 13 

    Results .......................................................................................................................... 15  iSCSI Performance Comparison ........................................................................... 15 

    Conclusions and Recommendations ......................................................................... 17  Acknowledgements ..................................................................................................... 18  Tables

    Table 1: CX3 FC/iSCSI Array Features – all figures are for two Storage Processors .................... 8 

    Table 2: Dell iSCSI Storage array Features .................................................................................... 9 

    Table 3: iSCSI Performance Data ................................................................................................. 15 

    Figures

    Figure 1: The Dell PowerVault NX1950 High Availability storage array .......................................... 7 

    Figure 2: The Dell/EMC CX3-10c, 20c and 40c with One Disk Array Enclosure (Standby Power Supply not shown) .................................................................................................................... 8 

    Figure 3: The Dell/EMC AX150i (Uninterruptible Power Supply not shown) .................................. 8 

    Figure 4: ESX Two NIC Configuration for iSCSI ........................................................................... 10 

    Figure 5: ESX Four NIC Configuration for iSCSI ........................................................................... 11 

    Figure 6: Test Setup (AX150i, CX3-20c and CX3-40c not shown) ............................................... 14 

  • May 2007 Page 3 Dell Enterprise Technology Center

    Figure 7: iSCSI Performance ......................................................................................................... 15 

    For Further Information and Discussion

    Visit our Dell TechCenter wiki at http://www.delltechcenter.com/page/iSCSI+and+VMware for more details on how to attach Dell iSCSI storage to VMware, to discuss this paper, and to contribute your expertise on iSCSI for VMware.

    Talk Back

    Tell us how the Dell Scalable Enterprise Technology Center can help your organization better simplify, utilize, and scale enterprise solutions and platforms. Send your feedback and ideas to [email protected] or visit us at dell.com/TechCenter.

  • May 2007 Page 4 Dell Enterprise Technology Center

    Section 1 Executive Summary

    New iSCSI storage arrays from Dell Inc. provide cost-effective, easy-to-deploy shared storage solutions for applications like the VMware Infrastructure 3 server virtualization software. In this paper features and performance of the Dell™ PowerVault™ NX1950, the Dell/EMC CX3 line of Fibre Channel/iSCSI combination storage arrays, and the Dell/EMC AX150i are compared, instructions for using with VMware are given, and recommendations are made when to use which.

  • May 2007 Page 5 Dell Enterprise Technology Center

    Section 2 Introduction

    Server virtualization programs such as VMware run best when the datacenter is organized into “farms” of servers that are connected to shared storage. By placing the virtual machines’ virtual disks on storage area networks accessible to all the virtualized servers, the virtual machines can be migrated from one server to another within the farm for purposes of load balancing or failover. VMware Infrastructure 3 uses the VMotion live migration facility in its Distributed Resource Scheduling feature and provides a High Availability component which takes advantage of shared storage to quickly boot up a virtual machine on a different ESX server after the original ESX server fails. Shared storage is key to enabling VMotion because, when a virtual machine is migrated from one physical server to another, the virtual machine’s virtual disk doesn’t actually move. Only the virtual disk’s ownership is changed while it continues to reside in the same place.

    The traditional networking technology employed in such storage area networks uses the Fibre Channel (FC) interface. Products such as the Dell/EMC line of Fibre Channel storage arrays provide excellent performance, reliability and functionality but can require specialized hardware and skills to set up and maintain. The Fibre Channel storage network starts with the fabric, which involves the use of FC host bus adapters (HBAs) in each server, connected by fiber cables to one or more FC switches, which in turn can network multiple storage arrays, each supporting a scalable number of high speed disk enclosures. An application’s request for an input or output (IO) to storage originates as a SCSI (Small Computer System Interface) request, is packed into an FC packet by the FC HBA, and sent down the fiber cable to the FC switch for dispatch to the storage array that contains the requested data, similar to the way Internet Protocol (IP) packets are sent over Ethernet.

    For smaller IT shops or for those that are just starting out in the virtualization arena, an alternate shared storage paradigm is emerging that employs iSCSI (Internet SCSI) to connect the servers to the storage. In this case the communication between the server and the data storage uses standard Ethernet network interface cards (NICs), switches and cables. SCSI IO requests are packed into standard Internet protocol packets and routed to the iSCSI storage through Ethernet switches and routers. With iSCSI customers can leverage existing networking expertise and equipment to simplify their implementation of a storage network. Like Fibre Channel, iSCSI supports block-level data transmission for all applications, not just VMware. For security iSCSI provides CHAP authentication as well as IPSEC encryption. An excellent introduction to iSCSI can be found in Travis Vigil’s article in the May 2007 Power Solutions, “iSCSI: Changing the Economics of Storage, Part 1-Understanding iSCSI in Enterprise Environments” (http://www.dell.com/downloads/global/power/ps2q07- 20070335-Vigil.pdf).

    Servers can communicate with iSCSI storage using two methods. The first involves the use of an add-in card called an iSCSI hardware initiator or host bus adapter, analogous to the Fibre Channel HBA, which connects directly to the datacenter’s Ethernet infrastructure. The second does the iSCSI conversion in software and sends the Ethernet packets through the standard Ethernet NIC in

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    the server. This study focuses on the use of the software initiator, which is supported by VMware.

    In the past two years Dell has introduced three iSCSI platforms, the Dell PowerVault NX1950, the Dell/EMC CX3 line of combination storage processors (which offer both iSCSI and Fibre Channel connectors) and the Dell/EMC AX150i. The three are designed for different sized customers and varying environments but all are easy to configure to provide storage to VMware hosts.

    This paper will describe Dell’s three iSCSI storage offerings, document how to configure them with VMware, and then, using a database workload running on two virtual machines, present performance results comparing the three platforms.

    The performance results shown in this paper represent a single, high-level view of the performance of the different arrays with a simple virtualization workload running on only 5 disks in each array. Typical customer use scenarios will employ larger disk arrays supporting a variety of applications, which may result in varying performance results.

  • May 2007 Page 7 Dell Enterprise Technology Center